From: Mark Rutland <mark.rutland@arm.com>
To: Dave Martin <Dave.Martin@arm.com>
Cc: catalin.marinas@arm.com, tengfeif@codeaurora.org,
will.deacon@arm.com, james.morse@arm.com,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 2/3] arm64: stacktrace: Factor out backtrace initialisation
Date: Fri, 28 Jun 2019 12:27:38 +0100 [thread overview]
Message-ID: <20190628112737.GH36437@lakrids.cambridge.arm.com> (raw)
In-Reply-To: <20190621155047.GE2790@e103592.cambridge.arm.com>
On Fri, Jun 21, 2019 at 04:50:48PM +0100, Dave Martin wrote:
> On Thu, Jun 06, 2019 at 01:54:01PM +0100, Mark Rutland wrote:
> > From: Dave Martin <Dave.Martin@arm.com>
> >
> > Some common code is required by each stacktrace user to initialise
> > struct stackframe before the first call to unwind_frame().
> >
> > In preparation for adding to the common code, this patch factors it
> > out into a separate function start_backtrace(), and modifies the
> > stacktrace callers appropriately.
> >
> > No functional change.
> >
> > Signed-off-by: Dave Martin <dave.martin@arm.com>
> > Signed-off-by: Mark Rutland <mark.rutland@arm.com>
>
> Ack (from memory you just added the CONFIG_FUNCTION_GRAPH_TRACER stuff,
> the lack of which was causing build failures in my original version).
You handled that in the version of the seires this was picked from [1].
I removed the tsk parameter, which now gets added in patch 3. I can
re-add that to this patch, or leave this as-is -- I have no strong
feelings either way.
> Have you added any new calls to start_backtrace() here?
No; I have not added any new calls.
Thanks,
Mark.
[1] http://lists.infradead.org/pipermail/linux-arm-kernel/2018-April/572687.html
>
> Cheers
> ---Dave
>
> > ---
> > arch/arm64/include/asm/stacktrace.h | 10 ++++++++++
> > arch/arm64/kernel/process.c | 6 +-----
> > arch/arm64/kernel/time.c | 6 +-----
> > arch/arm64/kernel/traps.c | 13 ++++++-------
> > 4 files changed, 18 insertions(+), 17 deletions(-)
> >
> > diff --git a/arch/arm64/include/asm/stacktrace.h b/arch/arm64/include/asm/stacktrace.h
> > index 4dd569592e65..18f90bf1385c 100644
> > --- a/arch/arm64/include/asm/stacktrace.h
> > +++ b/arch/arm64/include/asm/stacktrace.h
> > @@ -142,4 +142,14 @@ static inline bool on_accessible_stack(const struct task_struct *tsk,
> > return false;
> > }
> >
> > +static inline void start_backtrace(struct stackframe *frame,
> > + unsigned long fp, unsigned long pc)
> > +{
> > + frame->fp = fp;
> > + frame->pc = pc;
> > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > + frame->graph = 0;
> > +#endif
> > +}
> > +
> > #endif /* __ASM_STACKTRACE_H */
> > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> > index 3767fb21a5b8..122d88fccd13 100644
> > --- a/arch/arm64/kernel/process.c
> > +++ b/arch/arm64/kernel/process.c
> > @@ -509,11 +509,7 @@ unsigned long get_wchan(struct task_struct *p)
> > if (!stack_page)
> > return 0;
> >
> > - frame.fp = thread_saved_fp(p);
> > - frame.pc = thread_saved_pc(p);
> > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > - frame.graph = 0;
> > -#endif
> > + start_backtrace(&frame, thread_saved_fp(p), thread_saved_pc(p));
> > do {
> > if (unwind_frame(p, &frame))
> > goto out;
> > diff --git a/arch/arm64/kernel/time.c b/arch/arm64/kernel/time.c
> > index a777ae90044d..aa3489f3a452 100644
> > --- a/arch/arm64/kernel/time.c
> > +++ b/arch/arm64/kernel/time.c
> > @@ -49,11 +49,7 @@ unsigned long profile_pc(struct pt_regs *regs)
> > if (!in_lock_functions(regs->pc))
> > return regs->pc;
> >
> > - frame.fp = regs->regs[29];
> > - frame.pc = regs->pc;
> > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > - frame.graph = 0;
> > -#endif
> > + start_backtrace(&frame, regs->regs[29], regs->pc);
> > do {
> > int ret = unwind_frame(NULL, &frame);
> > if (ret < 0)
> > diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c
> > index ade32046f3fe..8053bbed8776 100644
> > --- a/arch/arm64/kernel/traps.c
> > +++ b/arch/arm64/kernel/traps.c
> > @@ -119,18 +119,17 @@ void dump_backtrace(struct pt_regs *regs, struct task_struct *tsk)
> > return;
> >
> > if (tsk == current) {
> > - frame.fp = (unsigned long)__builtin_frame_address(0);
> > - frame.pc = (unsigned long)dump_backtrace;
> > + start_backtrace(&frame,
> > + (unsigned long)__builtin_frame_address(0),
> > + (unsigned long)dump_backtrace);
> > } else {
> > /*
> > * task blocked in __switch_to
> > */
> > - frame.fp = thread_saved_fp(tsk);
> > - frame.pc = thread_saved_pc(tsk);
> > + start_backtrace(&frame,
> > + thread_saved_fp(tsk),
> > + thread_saved_pc(tsk));
> > }
> > -#ifdef CONFIG_FUNCTION_GRAPH_TRACER
> > - frame.graph = 0;
> > -#endif
> >
> > printk("Call trace:\n");
> > do {
> > --
> > 2.11.0
> >
> >
> > _______________________________________________
> > linux-arm-kernel mailing list
> > linux-arm-kernel@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
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next prev parent reply other threads:[~2019-06-28 11:28 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 12:53 [PATCH 0/3] arm64: stacktrace: improve robustness Mark Rutland
2019-06-06 12:54 ` [PATCH 1/3] arm64: stacktrace: Constify stacktrace.h functions Mark Rutland
2019-06-06 12:54 ` [PATCH 2/3] arm64: stacktrace: Factor out backtrace initialisation Mark Rutland
2019-06-21 15:50 ` Dave Martin
2019-06-28 11:27 ` Mark Rutland [this message]
2019-06-06 12:54 ` [PATCH 3/3] arm64: stacktrace: better handle corrupted stacks Mark Rutland
2019-06-21 16:37 ` Dave Martin
2019-06-28 11:32 ` Mark Rutland
2019-06-24 11:34 ` James Morse
2019-06-25 10:28 ` James Morse
2019-06-27 16:24 ` James Morse
2019-06-28 11:15 ` Dave Martin
2019-06-28 13:02 ` Mark Rutland
2019-07-01 10:48 ` Dave Martin
2019-07-01 11:22 ` Mark Rutland
2019-06-28 15:35 ` Mark Rutland
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